CVE-2025-14523 | Libsoup: libsoup: duplicate host header handling causes host-parsing discrepancy (first- vs last-value wins)

A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.

Published: 2025-12-11 Last update: 2026-06-29 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-14523 is rated Moderate Risk (46.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.50%). Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-14523

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.02% 0.50% +0.48%
2 2026-02-18 0.06% 0.02% -0.04%
3 2026-01-21 0.06%

Full EPSS history (4 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-14523

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.2 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
3.9 4.2 [email protected]

Weakness enumeration for CVE-2025-14523

OS Trackers for CVE-2025-14523

vendor priority summary link
debian not yet assigned CVE-2025-14523 not yet assigned priority: Debian including 2 source packages (libsoup2.4, libsoup3), 7 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5, resolved 2. https://security-tracker.debian.org/tracker/CVE-2025-14523
redhat high https://access.redhat.com/security/cve/CVE-2025-14523
suse high CVE-2025-14523 severity important: SUSE including 62 source package names (13.2-9.12:libpython3_11-1_0-3.11.13-1.1, 13.2-9.12:python311-base-3.11.13-1.1, …), 223 product×package rows across 44 product lines (Container suse/sl-micro/6.0/toolbox, Image SLE-Micro, … (44 product lines)): Fixed 219, First Fixed 4. https://www.suse.com/security/cve/CVE-2025-14523/
ubuntu medium CVE-2025-14523 medium priority: Ubuntu including 2 source packages (libsoup2.4, libsoup3), 13 status rows across 8 suites (bionic, focal, jammy, noble, plucky, questing, upstream, xenial): needed 9, ignored 2, needs-triage 1, released 1. https://ubuntu.com/security/CVE-2025-14523

Affected software / configurations for CVE-2025-14523

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-14523

URL Tags
https://access.redhat.com/errata/RHSA-2026:0421
https://access.redhat.com/errata/RHSA-2026:0422
https://access.redhat.com/errata/RHSA-2026:0423
https://access.redhat.com/errata/RHSA-2026:0836
https://access.redhat.com/errata/RHSA-2026:0867
https://access.redhat.com/errata/RHSA-2026:0868
https://access.redhat.com/errata/RHSA-2026:0905
https://access.redhat.com/errata/RHSA-2026:0906
https://access.redhat.com/errata/RHSA-2026:0907
https://access.redhat.com/errata/RHSA-2026:0908
https://access.redhat.com/errata/RHSA-2026:0909
https://access.redhat.com/errata/RHSA-2026:0911
https://access.redhat.com/errata/RHSA-2026:0925
https://access.redhat.com/errata/RHSA-2026:1509
https://access.redhat.com/errata/RHSA-2026:1569
https://access.redhat.com/errata/RHSA-2026:1570
https://access.redhat.com/errata/RHSA-2026:1571
https://access.redhat.com/errata/RHSA-2026:1572
https://access.redhat.com/security/cve/CVE-2025-14523
https://bugzilla.redhat.com/show_bug.cgi?id=2421349
https://gitlab.gnome.org/GNOME/libsoup/-/issues/472
cvelogic Threat Intelligence